Method and apparatus displaying double screen

ABSTRACT

An apparatus for displaying a double screen in a wide screen display device, the apparatus including a video interface to receive a first and a second video signal from a plurality of video signals according to a selection control signal, wherein each of the first and the second video signals have a general screen aspect ratio; a scaler to scale the first video signal to a resolution of a main screen and to scale the second video signal to a resolution of a subscreen with the general screen aspect ratio; and a control unit to output the selection control signal to display the double screen, control scaling of the first video signal and second video signal, and to simultaneously display the scaled first video signal on an area of a screen and the scaled second video signal on a portion of a remaining area of the screen.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 10/860,581and claims the priority of Korean Patent Application No. 2003-42115,filed on Jun. 26, 2003, in the Korean Intellectual Property Office, thedisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device and method, and moreparticularly, to an apparatus and method of displaying a double screenin a display device capable of displaying the double screen, in which amain screen is displayed at a 4:3 aspect ratio on the right or left sideof the entire screen and a subscreen is displayed at the 4:3 aspectratio on the remaining area.

2. Description of the Related Art

Currently, home televisions are being developed in such a way that theynot only provide users with image information but also allow users toenjoy television watching to the fullest, such that televisions can beconnected to communication networks and users can search information.Also, with the advent of wide screen televisions, images are displayedon a wide screen with a 16:9 aspect ratio instead of a screen with a 4:3aspect ratio of normal televisions. Thus, it has become possible toprovide users with high-quality broadcasting services.

Presently, most televisions include a video interface capable ofconnecting to various video signal inputs. When a user desires to watcha video signal aside from a video signal presently input through a videointerface, that is input through another video interface, the user mustconnect to the other video interface and navigate through an on screendisplay (OSD) menu using a keyboard or remote control of a television,thus manually converting input/output paths of the video signals.

In current televisions, a double screen can be displayed as apicture-in-picture (PIP) or picture-by-picture (PBP) screen.

FIG. 1A illustrates a conventional PIP screen. In FIG.1A, the PIP screenincludes a main screen and a subscreen displayed on a small portion ofthe main screen. If the double screen is displayed as the PIP screen, afirst video signal of the main screen is scaled to a 16:9 aspect ratioand is then displayed on the entire screen. If the first video signal ofthe main screen has a 4:3 aspect ratio, it is horizontally enlarged to a16:9 aspect ratio and is then displayed. Thus, distortion with respectto originally input screen information occurs. Also, in the PIP screen,a second video signal of the subscreen is scaled to a 16:9 aspect ratioand is then displayed on a portion of the entire screen at a specificsize. If the second video signal of the subscreen has the 4:3 aspectratio, it is horizontally enlarged to a 16:9 aspect ratio and is thendisplayed. Thus, distortion with respect to the originally input screeninformation occurs.

FIG. 1B illustrates a conventional PBP screen. In FIG. 1B, the entirePBP screen is divided into two parts, i.e., a subscreen 1 and asubscreen 2, wherein the two parts are respectively displayed. If thedouble screen is displayed as the PBP screen, the entire screen isdivided into two parts. The video signals of the two parts are scaled tothe same aspect ratio and are then displayed. If a first video signal ofthe subscreen 1 and an second video signal of the subscreen 2 have 4:3aspect ratios, they are vertically enlarged to 16:9 aspect ratios andare then displayed. Thus, distortion with respect to original inputscreen information occurs.

FIG. 1C illustrates a screen with the 16:9 aspect ratio on which anoriginal video signal with the 4:3 aspect ratio is displayed. In FIG.1C, parts on which the 4:3 aspect ratio format video signal is notdisplayed are processed to be black.

U.S. Pat. No. 6,515,643 discloses such double screen display.

When the double screen is displayed as the PIP screen, some parts of amain screen are covered by a subscreen. As a result, all information ofthe main screen cannot be displayed. Thus, if a user wishes to receivetwo types of video signals and simultaneously process such videosignals, the user has to scroll the main screen or close the subscreento watch the covered portion of the main screen. Moreover, if inputvideo signals have a 4:3 aspect ratio, they are enlarged horizontally(in a case of the PIP screen) or vertically (in a case of the PBPscreen) with respect to originally input screen information and are thendisplayed. Consequently, the user must watch a distorted screen.

SUMMARY OF THE INVENTION

The present invention provides an apparatus and method for displaying adouble screen, in which a main screen is displayed at a 4:3 aspect ratioon the right or left side of a display device and a subscreen isdisplayed at the 4:3 aspect ratio on the remaining area, therebypreventing loss of main screen information and allowing a user to watchan undistorted screen.

According to an aspect of the present invention, there is provided anapparatus for displaying a double screen in a wide screen displaydevice. The apparatus comprises a video interface, a scaler, and acontrol unit. The video interface receives a first video signal and asecond video signal among various video signals input from outside thewide screen display device according to a selection control signal, thefirst video signal and the second video signal having general screenaspect ratios. The scaler scales the first video signal to a resolutionof a main screen with the general screen aspect ratio and scales thesecond video signal to a resolution of a subscreen with the generalscreen aspect ratio, according to a scaling control signal. The controlunit outputs the selection control signal for displaying the doublescreen, controls scaling of the first video signal and second videosignal according to a main screen selection signal of the first videosignal and a subscreen selection signal of the second video signal, andsimultaneously displays the scaled first video signal on an area of theentire screen and the scaled second video signal on the remaining areaof the entire screen.

The scaler scales the first video signal to a resolution of 1024×768, onthe entire screen with a resolution of 1280×768 and scales the secondvideo signal to a resolution of 256×192, on the entire screen with theresolution of 1280×768.

The control unit operates such that the first video signal and thesecond video signal are displayed at their original aspect ratioswithout any distortion and an input video signal is not obscured byanother video signal.

The control unit converts the main screen into the subscreen and thesubscreen into the main screen according to a screen conversion signalinput from outside the wide screen display device.

The main screen is converted into the subscreen, the control unitoutputs the scaling control signal to gradually reduce the main screenwhile maintaining the general screen aspect ratio of the main screen,and when the subscreen is converted into the main screen, the controlunit outputs the scaling control signal to gradually enlarge the subscreen while maintaining the general screen aspect ratio of thesubscreen.

A process of gradual screen conversion is displayed on the wide screendisplay device.

According to another aspect of the present invention, there is provideda method of displaying a double screen. The method comprises receiving afirst video signal and a second video signal among various video signalsinput from outside the wide screen display device according to aselection control signal, the first video signal and the second videosignal having general screen aspect ratios, scaling the first videosignal to a resolution of a main screen with the general screen aspectratio and scaling the second video signal to a resolution of a subscreenwith the general screen aspect ratio, according to a scaling controlsignal, and displaying the scaled first video signal on an area of theentire screen and the scaled second video signal on the remaining areaof the entire screen.

The method further comprises converting the main screen of the firstvideo signal into the subscreen of the second video signal and thesubscreen of the second video signal into the main screen of the firstvideo signal.

The method further comprises, when the main screen is converted into thesubscreen, outputting the scaling control signal to gradually reduce themain screen while maintaining the general screen aspect ratio of themain screen, and when the subscreen is converted into the main screen,outputting the scaling control signal to gradually enlarge the subscreenwhile maintaining the general screen aspect ratio of the subscreen.

A process of gradual screen conversion is displayed on the wide screendisplay device.

When the first video signal is scaled to a resolution of a main screenwith the general screen aspect ratio and the second video signal isscaled to a resolution of a subscreen with the general screen aspectratio, according to a scaling control signal, the first video signal isscaled to a resolution of 1024×768 and the second video signal is scaledto a resolution of 256×192.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments taken in conjunction with the accompanying drawings inwhich:

FIGS. 1A through 1C illustrate a conventional double-screen display;

FIG. 2 is a block diagram of an apparatus displaying a double screenaccording to an embodiment of the invention;

FIGS. 3A and 3C through 3C illustrate double screens displayed by theapparatus of FIG. 2; and

FIG. 4 is a flowchart illustrating a method of displaying a doublescreen according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below to explain the presentinvention by referring to the figures.

The present invention will now be described more fully with reference tothe accompanying drawings, in which a preferred embodiment of theinvention is shown. In the drawings, like reference numerals are used torefer to like elements throughout.

FIG. 2 is a block diagram of an apparatus for displaying a double screenaccording to the present invention. The apparatus includes a videointerface 200, a video decoder 201, a deinterlacer 202, a scaler 203, adisplay unit 204, and a control unit 205. In the present invention, thevideo interface 200 includes a D-SUB terminal 200-1, a digital videointeractive (DVI) terminal 200-2, an S (separate)—VIDEO terminal 200-3,a television tuner terminal 200-4, and a COMPOSITE terminal 200-5.

FIGS. 3A through 3C are views for explaining double screens displayed bythe apparatus of FIG. 2 according to the present invention. In FIG. 3A,a main screen is displayed on the left side of the entire screen at a4:3 aspect ratio and a subscreen is displayed on the remaining area ofthe entire screen at the 4:3 aspect ratio. In FIG. 3B, the main screenis displayed on the right side of the entire screen at the 4:3 aspectratio and the subscreen is displayed on the remaining area of the entirescreen at the 4:3 aspect ratio. In FIG. 3C, when a screen is converted,the main screen is converted into the subscreen by gradual reduction ofthe main screen and the subscreen is converted into the main screen bygradual enlargement of the subscreen. For example, the gradual reductionand gradual enlargement is performed at a constant 4:3 aspect ratio.

FIG. 4 illustrates a flowchart describing a method of displaying adouble screen according to the present invention. The method includesdetermining whether to display a double screen (operation 400),selecting and confirming an input video signal of a main screen and aninput video signal of a subscreen to be displayed as the double screen(operation 401), determining whether a picture with picture (PWP) screenis selected to display the double screen (operation 402), displaying thedouble screen as a conventional PIP or PBP screen (operation 403),displaying a main screen on the left or right side of a display unit ata resolution of 1024×768 (4:3) (operation 404), displaying a subscreenon the remaining area of the display unit at a resolution of 265×192(4:3) (operation 405), determining whether to perform screen conversion(operation 406), and converting the main screen into the subscreen bygradually reducing the main screen and converting the subscreen into themain screen by gradually enlarging the subscreen (operation 407).

The subscreen is displayed on a portion of the remaining area of thescreen that is not used to display the main screen, wherein theremaining area of the screen is equal to an entire displayable screenarea minus a screen area used to display the main screen.

An apparatus for simultaneously displaying a double screen is describedwith reference to FIGS. 2 and FIGS. 3A through 3C.

The video interface 200 receives a variety of video signals input froman external source. In the present invention, the video interface 200receives video signals transmitted from any of three external devices (aPC, a game console, and a television). However, the number of externaldevices is not limited to three.

The video interface 200 receives video signals transmitted from a PC(not shown) through the D-SUB terminal 200-1 and the DVI terminal 200-2.

The video interface 200 receives a video signal transmitted from a gameconsole (not shown) through the S-VIDEO terminal 200-3. Here, an S-VIDEOsignal is formed by performing video transmission using two signals,i.e., a luminance signal Y and a chroma signal C, and the chroma signalC is formed by phase modulating two color difference signals of acomposite signal. “S-VIDEO” is named in the sense that the luminancesignal Y and the chroma signal C are separated from a composite signal.Use of S-VIDEO has begun with the development of high-definition videodevices such as S-VHS, which is advantageous in that display qualitysuperior to composite connection can be easily obtained.

Also, the video interface 200 receives video signals transmitted from atelevision (not shown) through the television tuner terminal 200-4 andthe COMPOSITE terminal 200-5.

When the double screen is displayed, the video interface 200 outputs afirst video signal and a second video signal under the control of thecontrol unit 205. Here, the first video signal and the second videosignal are output from one of the D-SUB terminal 200-1, the DVI terminal200-2, the S-VIDEO terminal 200-3, the television tuner 200-4, and theCOMPOSITE terminal 200-5. Here, it is assumed that the first videosignal and the second video signal have a general screen aspect ratio of4:3.

Among the video signals input to the video interface 200, the videosignal transmitted from the PC (not shown) through either the D-SUBterminal 200-1 or the DVI terminal 200-2 is directly output to thescaler 203.

However, among the video signals input to the video interface 200, thevideo signal transmitted from the game console (not shown) througheither the S-VIDEO terminal 200-3 or the video signal transmitted fromthe television (not shown) through either the television tuner terminal200-4 or the COMPOSITE terminal 200-5 is output to the video decoder201.

The video decoder 201 decodes the video signal output from the videointerface 200 through one of the S-VIDEO terminal 200-3, the televisiontuner terminal 200-4, and the COMPOSITE terminal 200-5 and outputs thedecoded video signal to the deinterlacer 202.

The deinterlacer 202 deinterlaces the decoded video signal and outputsthe resulting signal to the scaler 203.

The scaler 203 scales the received video signal to a resolution suitablefor a specification of the display unit 204. In addition, the scaler 203adjusts precise control functions of many factors that determine imagesas well as the resolution and outputs the processed video signal to thedisplay unit 204. Here, the display unit 204 has a wide screen aspectratio of 16:9, and the scaler 203 scales the received video signal to aresolution of 1280×768, which is suitable for the wide screen aspectratio of 16:9, and outputs the scaled signal.

However, if a user selects a double screen display signal, the scaler203 performs scaling for displaying a double screen under the control ofthe control unit 205.

The control unit 205 receives the double screen display signal inputthrough a keypad (not shown) or remote control (not shown). The controlunit 205 then outputs an on screen display (OSD) menu to the displayunit 204. Here, the OSD menu includes a PIP screen, a PBP screen, and aPWP screen that are to be selected by the user for displaying a doublescreen. In addition, the control unit 205 receives a first videoselection signal and a second video selection signal.

The first video signal of the main screen may be output from one of theD-SUB terminal 200-1, the DVI terminal 200-2, the S-VIDEO terminal200-3, the television tuner 200-4, and the COMPOSITE terminal 200-5output from the video interface 200.

Similarly, the second video signal of the subscreen is output from oneof the D-SUB terminal 200-1, the DVI terminal 200-2, the S-VIDEOterminal 200-3, the television tuner 200-4, and the COMPOSITE terminal200-5 output from the video interface 200.

If the user selects one of the PIP screen and PBP screen from the OSDmenu output by the control unit 205, the control unit 205 issues ascaling command to the scaler 203 so as to output a screen shown in FIG.1A or 1B.

If the user selects the PWP screen from the OSD menu output by thecontrol unit 205, the control unit 205 issues a PWP scaling command tothe scaler 203 so as to output a screen shown in FIG. 3A or 3B.

When receiving the PWP scaling command from the control unit 205, thescaler 203 scales the first video signal of the main screen to theresolution of 1024×768 (4:3) and scales the second video signal of thesubscreen to the resolution of 256×192 (4:3).

The control unit 205 displays the scaled first video signal and secondvideo signal on certain areas of the display unit 204, respectively.FIGS. 3A and 3B show displayed double screens, i.e., the main screen andthe subscreen, on the entire screen, that are controlled by the controlunit 205. Here, the main screen is a signal input from the PC and thesubscreen is a signal input from the television.

In FIG. 3A, the main screen is displayed on the left side of the entirescreen at a 4:3 aspect ratio and the subscreen is displayed on theremaining area of the entire screen at the 4:3 aspect ratio. The entirescreen of a wide screen display device has a resolution of 1280×768(16:9). The main screen is displayed on the left side of the entirescreen at a resolution of 1024×768 (4:3) and the subscreen is displayedon the remaining area of the entire screen at a resolution of 256×192(4:3).

In FIG. 3B, the main screen is displayed on the right side of the entirescreen at the 4:3 aspect ratio, and the subscreen is displayed on theremaining area of the entire screen at the 4:3 aspect ratio. The entirescreen of the wide screen display device has the resolution of 1280×768(16:9). The main screen is displayed on the right side of the entirescreen at the resolution of 1024×768 (4:3), and the (subscreen isdisplayed on the remaining area of the entire screen at the resolutionof 256×192 (4:3).

The control unit 205 receives a screen conversion signal from the user.Screen conversion refers to converting a presently displayed main screeninto a subscreen and the subscreen into the main screen. Once receivingthe screen conversion signal, the control unit 205 issues a scalingcommand for screen conversion to the scaler 203. In FIG. 3C, in screenconversion through scaling of the scaler 203, the main screen isconverted into the subscreen by gradually reducing the main screen andthe subscreen is converted into the main screen by gradually enlargingthe subscreen.

The scaler 203 converts the main screen with the resolution of 1024×768(4:3) into the subscreen with the resolution of 256×192 (4:3) bygradually reducing the main screen. Gradual reduction is also carriedout at a 4:3 ratio. At this time, a process of converting the mainscreen into the subscreen is displayed on the display unit 204 by thecontrol unit 205.

The scaler 203 converts the subscreen with the resolution of 256×192(4:3) into the main screen with the resolution of 1024×768 (4:3) bygradually enlarging the subscreen. Gradual enlargement is also carriedout at a 4:3 ratio. At this time, a process of converting the subscreeninto the main screen is displayed on the display unit 204 by the controlunit 205.

A method of displaying a double screen is described below with referenceto FIGS. 3A through 3C and FIG. 4.

The control unit 205 displays the double screen according to whether thedouble screen display signal is received from the user (operation 400).The user determines whether to display the double screen.

The control unit 205 receives the double screen display signal inputthrough a keypad (not shown) or a remote control (not shown). Thecontrol unit 205 then outputs the OSD menu to the display unit 204.Here, the OSD menu includes the PIP screen, the PBP screen, and the PWPscreen that are to be selected by the user.

The control unit 205 receives an input video signal of the main screenand an input video signal of the subscreen to simultaneously display thedouble screen (operation 401).

Here, it is assumed that the first video signal and the second videosignal have general screen aspect ratios of 4:3. The first video signalof the main screen may be output from one of the D-SUB terminal 200-1,the DVI terminal 200-2, the S-VIDEO terminal 200-3, the television tuner200-4, and the COMPOSITE terminal 200-5 output from the video interface200. Similarly, the second video signal of the subscreen may be outputfrom one of the D-SUB terminal 200-1, the DVI terminal 200-2, theS-VIDEO terminal 200-3, the television tuner 200-4, and the COMPOSITEterminal 200-5 output from the video interface 200.

In operation 402, it is determined whether a user selects the PWP screenfrom the OSD menu to display the double screen.

If the user selects the PIP screen or PBP screen from the OSD menuoutput by the control unit 205 to display the double screen, the doublescreen is displayed as a conventional PIP or PBP screen (operation 403).If the user selects the PIP screen or PBP screen from the OSD menuoutput by the control unit 205, the control unit 205 issues the PIP orPBP scaling command to the scaler 203 to display the screen shown inFIG. 1A or 1 B. The scaler 203 performs scaling suitable for the PIPscreen or PBP screen and then outputs the scaled video signal to thedisplay unit 204 under the control of the control unit 205.

If the user selects the PWP screen from the OSD menu output by thecontrol unit 205 to display the double screen, the main screen isdisplayed on the left or right side of the display unit 204 at theresolution of 1024×768 (4:3) (operation 404) and the subscreen isdisplayed on the remaining area of the display unit 204 at theresolution of 256×192 (4:3) (operation 405).

If the user selects the PWP screen from the OSD menu output by thecontrol unit 205, the scaler 203 issues the PWP scaling command to thescaler 203 to display a screen shown in FIG. 3A or 3B. Upon receivingthe PWP scaling command from the control unit 205, the scaler 203 scalesthe first video signal of the main screen to the resolution of 1024×768(4:3) and scales the second video signal of the subscreen to theresolution of 256×192 (4:3).

The control unit 205 displays the scaled first video signal and secondvideo signal on certain areas of the display unit 204, respectively.FIGS. 3A and 3B show displayed double screens, i.e., the main screen andthe subscreen, on the entire screen under the control of the controlunit 205.

In FIG. 3A, the main screen is displayed on the left side of the screenat the resolution of 1024×768 and the subscreen is displayed on aportion of a remaining area of the screen at the resolution of 256×192.In FIG. 3B, the main screen is displayed on the right side of the screenat the resolution of 1024×768 and the subscreen is displayed on aportion of a remaining area of the screen at the resolution of 256×192.

The control unit 205 determines whether the main screen and thesubscreen of a presently displayed double screen are converted accordingto whether the screen conversion signal is received from the user(operation 406).

Then, the control unit 205 converts the main screen into the subscreenby gradually reducing the main screen and converting the subscreen intothe main screen by gradually enlarging the subscreen (operation 407).

The control unit 205, receiving the screen conversion signal, issues thescaling command for screen conversion to the scaler 203. In FIG. 3C, inscreen conversion, the main screen is converted into the subscreen bygradually reducing the main screen and the subscreen is converted intothe main screen by gradually enlarging the subscreen.

The scaler 203 converts the main screen with the resolution of 1024×768(4:3) into the subscreen with the resolution of 256×192 (4:3) bygradually reducing the main screen. Gradual reduction is also carriedout at a 4:3 ratio. At this time, a process of converting the mainscreen into the subscreen is displayed on the display unit 204 by thecontrol unit 205. The scaler 203 converts the subscreen with theresolution of 256×192 (4:3) into the main screen with the resolution of1024×768 (4:3) by gradually enlarging the subscreen. Gradual enlargementis also carried out at a 4:3 ratio. At this time, a process ofconverting the subscreen into the main screen is displayed on thedisplay unit 204 by the control unit 205.

As described above, according to the invention, it is possible toprovide undistorted screen information to a user by simultaneouslydisplaying a main screen and a subscreen while maintaining a 4:3 aspectratio of input video signals.

In addition, since the main screen is converted into the subscreen bygradually reducing the main screen and the subscreen is converted intothe main screen by gradually enlarging the subscreen, it is possible tominimize loss of information in screen conversion.

While the present invention has been particularly shown and describedwith reference to an exemplary embodiment thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the invention as defined by the appended claims and theirequivalents.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. An apparatus for displaying a double screen in a display devicecapable of displaying the double screen, the apparatus comprising: avideo-interface receiving first and second video signals from among aplurality of video signals according to a selection control signal; ascaler scaling the first and second video signals to a resolution of amain screen and a resolution of a subscreen, respectively, according toa scaling control signal In a non-overlap manner; and a control unitcontrolling the scaling of the first and second video signals andsimultaneously displaying each scaled video display on a respective areaof a screen of the display device; wherein the control unit is capableof automatically adjusting the resolution of one of the first and secondvideo signals when the user adjust the resolution of the other of thefirst and second video signals so as to maintain the first and secondvideo signals in the non-overlap manner.
 2. The apparatus of claim 1,further comprising an on screen display menu on the display unit for auser to select to display the double screen, wherein the on screendisplay menu Includes at least one of a picture-in-picture screen, apicture-by-picture screen, and a picture-with-picture screen.
 3. Theapparatus of claim 1, wherein the control unit outputs the selectioncontrol signal to display the double screen.
 4. The apparatus of claim3, wherein the control unit simultaneously displays the first videosignal on the screen and the second video signal on a portion of aremaining area of the screen.
 5. The apparatus of claim 1, wherein thevideo interface comprises a D-SUB terminal, a digital video interactiveterminal.
 6. The apparatus of claim 5, wherein the D-SUB terminal and/orthe DVI terminal transmit video signals directly to the scaler.
 7. Theapparatus of claim 1, wherein the scaler adjusts the resolution andoutputs a processed video signal of the adjusted first and second videosignals to the display device.
 8. The apparatus of claim 1, wherein thecontrol unit converts the main screen into the subscreen and thesubscreen into the main screen.
 9. The apparatus of claim 1, whereinwhen the main screen is converted Into the subscreen, the control unitoutputs the scaling control signal to gradually reduce the main screenwhile maintaining the aspect ratio of the main screen, and when thesubscreen is converted into the main screen, the control unit outputsthe scaling control signal to gradually enlarge the sub screen whilemaintaining the aspect ratio of the subscreen.
 10. A method ofdisplaying a double screen in a display device capable of displaying thedouble screen, the method comprising: receiving first and second videosignals from among a plurality of video signals according to a selectioncontrol signal; scaling the first and second video signals to aresolution of a main screen and a resolution of a subscreen,respectively, according to a scaling control signal; displaying thescaled first and second video signals simultaneously such that thesubscreen Is located in a separate area from the main screen on a screenof the display device in a non-overlap manner; and displaying an onscreen display menu to select from among a plurality of displays todisplay the double screen,
 11. The method claim 10 wherein the displaysto display the double screen comprise a picture-in-picture screen, apicture-by-picture screen, and a picture-with-picture screen.
 12. Themethod of claim 10, wherein the receiving first and second video signalscomprises receiving first and second video signals from a D-SUB terminaland a DVI terminal, respectively.
 13. The method of claim 10, furthercomprising displaying the main screen at either a left or a right edgeof the screen and displaying the subscreen on a portion of a remainingarea of the screen.
 14. The method of claim 13, further comprisingconverting the main screen into the subscreen and the subscreen into themain screen: wherein the main screen is converted into the subscreen bygradually reducing the main screen at a constant aspect ratio and thesubscreen Is converted into the main screen by gradually enlarging thesubscreen at the constant aspect ratio.